It’s clear to most citizens of California that wildfires have become more intense over the last few years. Researchers at UC Santa Barbara and the Nature Conservancy have compiled a new dataset of damage caused by wildfires in California in areas protected by the state of California. (Some of the data does not include fires on lands protected by federal agencies, such as the U.S. Forest Service, National Park Service, and the BLM). The report illustrates how the recent set of severe fires fits into a broader trend of increasing burn area and damage over the past 40 years.

The researchers studied data on fire perimeters and estimates of damages for each fire and used the information to calculate trends involving the number and timing of fires throughout the state by time of year. They also calculated the total area burned and specifically identified the amount of wildland urban-interface burned. These are areas where houses intermingle with wildland vegetation, and are of particular concern to those studying wildfire.

Andrew Plantinga. UCSB photo.

“The main finding is that the recent severe fires in California — including the Thomas fire in 2017 and the Camp fire in 2018 — are part of a trend in California over the past four decades,” said Andrew Plantinga, an economics professor at UC Santa Barbara’s Bren School of Environmental Science & Management. “The trend is toward more wildfires that burn larger areas and cause more damage.”

The number of acres burned per year has not only been increasing, the report found, it is also accelerating. And this increase isn’t only during the season’s peak, from June through October. The state is also seeing a longer fire season, with more acres burned in late fall than in the past. And while greater burn areas don’t automatically translate to greater damages, the researchers found that these, too, have been on the rise.

“I expected the recent severe fires to be outliers, and they are,” said Plantinga, “but it’s also clear that they represent part of a trend toward larger and more damaging fires.”

The report is part of a larger effort to estimate the costs associated with a business-as-usual approach to development in California, when considering the potential impacts of climate change. The team had previously found that interventions on natural and working lands — like forests, farms and rangelands — can contribute 2.5 times the emissions reductions by 2050 as residential and commercial sectors combined.

What’s more, for every dollar spent on implementing land-use strategies, close to fifty cents would be recouped in economic benefits. And that’s without accounting for other positive impacts, the previous report states.

Civilian and Firefighter Deaths on wildfires in California that occurred on State Responsibility Area lands, 1979 – 2017.Estimated Value of Structure Losses (in 2018 dollars) for State Responsibility Area Fires, by Year, 1979 – 2018.

Map of Structure Losses and Fire Perimeters for State Responsibility Area Fires, 1979 – 2018.

Pamela Ren Larson and Dennis Wagner of the Arizona Republic studied nearly 5,000 small communities around the West to find out how how many of them are facing large-scale wildfire risk similar to Paradise, California where 19,000 structures burned and 85 people were killed in the Camp Fire. After finding 526 places that have a higher wildfire potential than Paradise, nine reporters set out to report on nine communities in eight states.

Click on the tweet below to reveal the detailed thread which is an introduction to the very detailed reporting that you will see when you click on the links therein. Here is a link to the main story.

About six months ago, I began an enormous project: To find other places like Paradise, California, at risk of wildfire in the West. With wildfire season getting longer, we set out to find these high-hazard communities, ahead of the fire. (THREAD)

BOZEMAN — Ray Rasker, who has researched wildfire for more than a decade as the executive director of Bozeman-based nonprofit Headwaters Economics, makes a bold claim about wildfire and its human impacts.

“We don’t have a forest fire problem, we have a home ignition problem,” he said. “As soon as you come to that realization, it changes your view on wildfire.”

(UPDATE: Ray Rasker contacted us in a comment, below, to say, “The top quote [above] was something I mentioned to the reporter as something that was said by Dr. Jack Cohen, a long-time Fire Science Researcher with the U.S. Forest Service. It’s not my quote and I’m not trying to take credit for Jack’s insightful comment.”)

Often we hear about the costs of suppressing wildfires, but the cost of fire trucks, firefighters, dozers, and aircraft are only part of that cost.

Another excerpt:

Some of a community’s willingness to change growth policies, subdivision regulations, building codes, and the like can be attributed to economics. Although significant, the money spent putting out a wildfire is minor — about 9 percent — relative to fire’s total financial impact, Rasker said. “Fifty percent of the cost is borne by the community. That’s businesses that close, that’s the loss of tax revenue during the fire, that’s the cost of reconstruction — restoring your wetland, for example. Your tax base goes up in flames.”

When economic losses become severe enough, elected officials find the political cover they need to push for additional regulation. Rasker said he’s seen the dynamic at work in several communities CPAW has worked with, including Flagstaff, Arizona; Boulder, Colorado; and San Diego, California. “Now it’s not planning as a liberal agenda; now it suddenly becomes something that’s fiscally responsible.”

Such regulations can include mandating better egress roads to make subdivision evacuations safer, requiring new buildings to be constructed with fire-resistant material, and developing landscaping guidelines for homeowners. There was a time, Rasker said, when municipal fire codes mandating safety measures like sprinkler systems and marked fire exits were all but nonexistent, resulting in casualties. “In an urban environment, we’ve fixed this problem,” he said. “But when the houses are surrounded by trees on the outside of town, suddenly none of those rules apply,” Rasker said, referencing a lack of regulations and enforcement in many rural areas.

How you tell a story influences what conclusions people draw from it (think Aesop’s Fables). Over the past decade, the overarching American wildfire narrative has become fairly focused on three dynamics: fuels buildup due to suppression, climate change, and the expanding wildland-urban interface (WUI). But what are these narratives based on?

There is a fair bit of research and debate as to when and where fuel overloading and climate change will have the most influence, in fact too much to be easily citable here. However, according to research for a paper that I’m developing with Matt Thompson of the Rocky Mountain Research Station and Courtney Schultz of Colorado State University, few data support the WUI story. Specifically, only limited data support the arguments for why and how the WUI is contributing to the wildfire problem.

For instance, a commonly cited concern is that 50–95 percent of wildfire suppression costs can be attributed to the protection of private property in the WUI. However, when our team followed the citations for this statement, we found that they all led back to data from a single 2006 Office of Inspector General (OIG) report (PDF, 1.57 MB). Further, the report reached that particular conclusion using data that most social scientists would find problematic at best. Stay tuned for my team’s paper to learn more about that report’s limitations.* We have found a few studies that examine the breakdown of suppression costs in a more rigorous manner, using meaningful metrics (e.g., the number of homes near the fire perimeter and the percent of private land). But, while they do find a positive association between homes being located in the WUI and suppression costs, none demonstrate causality or conclude that the costs of protecting private property come close to the low end of OIG’s estimates. Nor can we find any study that tracks changes in the WUI with changes in suppression costs over time, even though a key perceived “problem” with the WUI is that its expansion will automatically increase wildfire suppression costs.

Similarly, although it is often stated that wildfire-related housing loss is increasing, it is hard to find any data that support or deny this claim, as wildfire-related housing loss hasn’t been tracked consistently until fairly recently. Further, even the existing data are problematic. For instance, the National Interagency Coordination Center (NICC) claims that 2,638 homes were lost nationally in 2015 (see page 9 of this NICC report, PDF, 830 KB); while CAL FIRE reports that 3,217 homes were destroyed in California alone that same year (see page 10 of this CAL FIRE report, PDF, 1.28 MB). Further, while it is too short of a time span to draw any solid conclusions, it is worth noting that both datasets suggest that higher losses are periodic and due to specific wildfire events. For example, the graph below, which I developed using NICC annual summary reports, illustrates that when excluding the state that lost the most residences in a given year — say Tennessee in 2016, the year of the Gatlinburg fires — home loss (shown in green) is relatively flat.

Inaccurate Stories Are Unlikely to Lead to Effective Solutions Accepting WUI narratives that lack sufficient supporting data can lead to developing solutions that are less likely to have the desired impact, because they may be targeting the wrong problem. Further, these proposed solutions may have unintended consequences because they don’t take existing data, or lack thereof, or the larger context into account. For instance, a common recommendation based on the WUI narrative is to limit development in fire-prone areas. However, while we do have fairly robust science concerning factors that make an individual home more fire resistant, we don’t have much information on what type of larger scale development is associated with improved wildfire outcomes. There are only a few relevant studies, and they offer conflicting “solutions.” For example, some studies suggest clustered housing would help with decreasing suppression costs, but others suggest clustered housing would lead to more losses.

Another common recommendation based on the WUI narrative is to form a national fire-insurance program similar to the National Flood Insurance Program, which appears to be seen as a means of ensuring that WUI residents bear the cost of living there. This recommendation ignores the significant evidence concluding that the National Flood Insurance Program has done little to shift the cost burden from federal taxpayers (and in fact has probably increased it) or to limit housing development in flood-prone areas. This argument also seems to assume that if individuals can’t obtain or afford insurance, then they will choose to not live in the WUI. However, there is no evidence that this is the case. It’s just as likely that individuals will continue to live there for a variety of reasons (e.g., amenities, affordability in other regards) and just take their chances, essentially making those with fewer resources even more vulnerable.

Further, insurance levers can raise an equity consideration: if insurance did have the desired effect, it is likely that only the wealthy would be able to live in the WUI since only they could afford to pay higher insurance premiums or to self-insure. It is worth asking whether that is an acceptable tradeoff.

Shifting Our Language Through this process, I have begun to question whether the WUI is still a useful construct. While it may have been useful at one point to draw attention to the increasing intermingling of housing and natural vegetation, it now seems to create an artificial distinction that may be misleading. I doubt many of those who lost their homes in the recent California wildfires, particularly in Santa Rosa, thought of themselves as living in the WUI. Further, a preliminary analysis by the University of Wisconsin shows that regarding the Tubbs Fire, many of the losses were not technically in the WUI. Instead, the largest portions of homes lost were in areas considered either too dense or not dense enough to be classified as the WUI. Forest Schafer’s recent blog post about how Lake Tahoe partners are rethinking their WUI is another example of the limitations of drawing artificial lines when assessing wildfire risk.

And then there is the question of how limiting development in the WUI would work. Beyond equity issues and the fact that we don’t have strong evidence regarding what “better” land-use planning for wildfire looks like, I always wonder, “So, where are people supposed to live then?” As one recent newspaper headline stated: “All Californians Live in Fire Country Now.” Perhaps just thinking about how we can best live in fire-prone landscapes may be a more useful way to frame the discussion, rather than creating artificial distinctions based on housing density and natural vegetation.

*This blog describes initial findings from a paper that Courtney, Matt and I are working on. The articles referenced in this blog post will be identified in that paper, which will be available on Treesearch once it is published.

Photo credit: Sarah McCaffrey

Sarah McCaffrey, Ph.D., is a research forester for the USDA Forest Service, Rocky Mountain Research Station. Her research focuses on the social aspects of fire management. This work has included projects examining wildfire risk perception, social acceptability of prescribed fire and thinning, characteristics of effective communication programs, and incentives for the creation and maintenance of defensible space. She has also initiated work examining social issues that occur during and after wildfires, including evacuation-decision making, agency-community interactions during fires, public perception of wildfire management overall, views on the Cohesive Strategy, and perceptions about what it means to be a fire adapted community. She received her Ph.D. in Wildland Resource Science in 2002 from the University of California at Berkeley.

When Dave Lasky was leading the effort in the Four Mile Fire Protection District not far from Boulder, Colorado conducting pre-fire mitigation near structures, he and others assumed that doing SOMETHING, cutting trees and building slash piles, would be better than doing nothing. They realized it would not be the total solution in the wildland-urban interface (WUI), but when the Fourmile Canyon Fire started on September 2, 2010 the Fire Protection District found out how wrong they were.

Map of the Fourmile fire near Boulder, showing heat detected by the MODIS satellite at 4:18 a.m. Sept. 8, 2010. Map by Wildfire Today and NASA.

After the ashes cooled, Dr. Jack Cohen, a U.S. Forest Service fire researcher who has investigated the effects on structures at numerous WUI fires, found what he has seen many times before (more details here). Most of the damaged homes, 83 percent in this case, ignited from airborne fire embers or surface fire spreading to contact the structure; not from high intensity crown fire or direct flame impingement.

The fuel reduction along travel corridors may have helped residents to evacuate, but the unburned slash piles, Mr. Lasky said, could have been a problem:

In several areas, our crew’s piles were associated with complete stand mortality. We created ladders into the canopy. At best, these unburned piles represented a sad waste of money, and at worst, it is possible that if we hadn’t treated them, these stands might not have carried fire.

“Doing something is not better than doing nothing. When the mitigation crew approached residents in the past, they often said, “I didn’t move up here to see my neighbors. I don’t want to cut trees.” In an effort to build momentum, we often performed work that we knew was not reflective of the best science, cutting fewer trees than we should have. This practice was in regard to both defensible space as well as shaded fuel-break projects. The hope was that as communities adjusted to the cosmetic changes, we’d be able to reenter and accomplish more.

“I still hear many colleagues say “let’s just get something done.” I believe this is wrong. We need to do it right or not do it at all. Half measures are proven to fail and engaging in them has great reputational costs. In the current climate of high-profile, catastrophic fires, I am not interested in fear mongering. But I am interested in applying our limited resources to only those communities that are fully committed.

“It’s not just about cutting trees in the wildland-urban interface. Fuels crews are run by firefighters. Perhaps they should be run by architects. In retrospect, we spent far too much money on fuels reduction and not enough on assisting residents with the installation of fire-resistant building materials and landscaping. Few of the homes lost were directly impacted by crown fire; rather, embers undoubtedly ignited the fine fuels around them, which eventually led to the loss of entire structures. In many instances, residents would have been better served by our crew putting a decorative stone perimeter around the structure. Many residents are capable of cleaning gutters, but less can move tons of gravel. We had chainsaws, and we knew how to use them. We should have picked up our shovels instead.”